SACRAMENTO — Children with a genetic disorder called 22q11.2 deletion syndrome, who frequently are believed to also have autism, often may be misidentified because the social impairments associated with their developmental delay may mimic the features of autism.
That’s according to a study by researchers with the UC Davis MIND Institute that is he first to examine autism in children with chromosome 22q11.2 deletion syndrome — or 22q — using rigorous gold-standard diagnostic criteria.
The research found that none of the 29 children in the study with 22q “met strict diagnostic criteria” for autism.
“This is very important because the literature cites rates of anywhere from 20 to 50 percent of children with the disorder also have an autism spectrum disorder,” said Kathleen Angkustsiri, study lead author and assistant professor of developmental-behavioral pediatrics.
“Our findings lead us to question whether this is the correct label for these children who clearly have social impairments. We need to find out what interventions are most appropriate for their difficulties.”
Evaluations should be performed to assess autism and guide the selection of appropriate therapies based on the children’s symptoms, such as language and communication delay, the researchers said. The study is published online in Springer’s Journal of Autism and Developmental Disorders.
A high prevalence of autism spectrum disorder has been reported in children with 22q– as high as 50 percent based on parent-report measures.
Children diagnosed with 22q may experience mild to severe heart anomalies, weakened immune systems and malformations of the head and neck and the roof of the mouth. They also experience developmental delay, with IQs in the borderline-to-low-average range.
They characteristically experience significant anxiety and appear socially awkward.
The disorder’s name also describes its location on the 22nd chromosome as well as the nature of the genetic mutation, which is associated with a variety of anatomical and intellectual deficits.
The risk of 22q is about 1 in 2000 in the general population. The condition is seen in individuals of all backgrounds.
A person with 22q has a 30 times greater risk of developing schizophrenia than individuals in the general population.
“Because of the high rates of psychiatric disorders in childhood and adulthood, 22q is a very special population for prospective study looking at what’s happening throughout childhood that might either increase risk or provide protection against some of the later developing serious psychiatric illnesses,” said Tony Simon, director of the chromosome 22q at the MIND Institute.
The researchers selected 29 children – 16 boys and 13 girls – for additional scrutiny, administering two tests.
The Autism Diagnostic Observation Schedule was administered to the children. The Social Communication Questionnaire, a 40-question parent screening tool for communication and social functioning was administered to their parents.
Typically, a diagnosis of autism spectrum disorder requires elevated scores on both a parent report measure, such as the SCQ, and a directly administered assessment such as the ADOS. Prior studies of autism in chromosome 22q have only used parent report measures.
Only five of the 29 children had scores in the elevated range on the ADOS diagnostic tool. Four of the five had significant anxiety. Only two – 7 percent – had SCQ scores above the cut off.
No child had both SCQ and ADOS scores in the relevant ranges that would lead to an ASD diagnosis.
“Over the years, a number of children came to us as part of the research or the clinical assessments that we perform, and their parents told us that they had an autism spectrum diagnosis. It’s quite clear that children with the disorder do have social impairments,” Simon said.
“But it did seem to us that they did not have a classic case of autism spectrum disorder. They often have very high levels of social motivation. They get a lot of pleasure from social interaction, and they’re quite socially skilled.”
Simon said that the team also noted that the children’s social deficits might be more a function of their developmental delay and intellectual disability than autism.
“If you put them with their younger siblings’ friends they function very well in a social setting,” Simon continued, “and they interact well with an adult who accommodates their expectations for social interaction.”
Angkustsiri said that further study is needed to assess more appropriate treatments for children with 22q, such as improving their communication skills, treating their anxiety, helping them to remain focused and on task.
— UC Davis Health News Office